Questions tagged [vector]
Mathematical vectors, operations on vectors and vectorized programming.
597
questions
2
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1
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Calculating power series of quantum operators on kets
I am using the "Quantum" add-on package to perform some quantum mechanical calculations using SU(1,1) generators. The code that I've developed reads
...
- 655
0
votes
0
answers
60
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streamplot for differntial equation
how I can use StreamPlot or VectorPlot to show x[t] and 1-x[t] and show convergence point in my plot with a different colour like a blue point?
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- 77
1
vote
1
answer
60
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Find binary vector within fixed distance to reference vector that maximizes the number of distances to a set of vector that are below a threshold
Input: A binary reference vector $r$, a multi-set of binary vectors $S$, and a distance function d between binary vectors of equal length. Assume that $r$ and all vectors in $S$ have the same length.
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- 33
1
vote
1
answer
76
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LinearOptimization - how to solve with vector constraints?
I have the following linear program that I am able to solve in MATLAB. However, I want to move to Mathematica.
For some fixed constants $n$, $\delta$ and $\varepsilon$ and fixed $(n+1)$-dimensional ...
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2
votes
1
answer
53
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Solving a vector diferential equation lead to ComplexInfinity Encountered non-numerical value for a derivative at t == 0
I'm trying to solve the following Vector PDE:
I implemented the following code:
...
- 561
1
vote
1
answer
44
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Using Through function with vectors
I have the vectors defined as follows:
v1={x1,y1,z1};
v2={x2,y2,z2};
v12=v2-v1;
v21=v1-v2;
I am passing an integer function for iteration purpose as follows:
...
- 755
2
votes
3
answers
230
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How to do column vector concatenation
Is it a way to do column vector concatenation?
u = {{1},{-1},{0}};
v = {{0},{1},{-1}};
w = {{-1},{0},{1}};
I would like a matrix of {u,v,w}
- 107
0
votes
0
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61
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Spherical Polar Coordinates VectorPlot3D
I understand the VectorPlot3D function allows you to plot a 3D vector ${Vx,Vy,Vz}$ as a function of $x,y,z$.
Is there a function that allows you to plot in ...
1
vote
1
answer
77
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VectorAngle[] relative to specific origin?
VectorAngle[] computes the angle between two vectors from the origin (I assume {0.0, 0.0, 0.0}).
Can we use a reference point ...
- 1,563
10
votes
1
answer
191
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VectorColorFunction not working at a few points
I use the following data to ListVectorPlot a vector field with the color indicating the vector direction. However, there seem to be some vectors not colored ...
- 4,226
0
votes
0
answers
50
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How to express elemental operations in matrix form?
I ran the following code:
X = Array[x, {5, 4}];
W = Array[w, {4, 3}];
Y = Array[y, {5, 3}];
D[Norm[X.W-Y, "Frobenius"]^2, {W}]//MatrixForm
However, mma ...
- 1
5
votes
1
answer
75
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Speed up dot and cross products for a list of vectors, in a "brick wall" pattern
Yesterday I asked a question on how to speed of computation of dot and cross products for a list of vectors, for which I received a nice answer from Henrik Schumacher.
Now I have a follow up question ...
- 613
8
votes
1
answer
304
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Speeding up cross and dot products for a list of vectors
I am working on a code where I perform dot and cross product operations on a large list of vectors multiple times. I am using MapThread to achieve this but I feel the speed of operation is not up to ...
- 613
-1
votes
1
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67
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1
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1
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80
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Convert a polynomial to a vector [duplicate]
I am trying to transform a generated polynomial terms into a vector, I used the command 'MonomialList',
...
- 31
0
votes
1
answer
56
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Total Spin Matrix Squared (Casimir Operator)
I am trying to get Mathematica to compute the Casimir operator of a 4 particle system of spin $1/2$ fermions. I have the following code which does not do what I would like it to.
...
- 137
0
votes
0
answers
72
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How to matricize a vector?
I am wondering how to represent a vector as a matrix, using specified dimensions. For example, MatrixForm[{a, b, c, d}] gives me a column vector. But I would want ...
0
votes
1
answer
94
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How do I find the unit vector in the direction of the minimal rate of change?
A ball falls on the surface $x^4 z+x^9 y^2+y^2 z^3=65$ at the point (-1,-3,2). How do I find a three-dimensional unit vector in the direction that the ball will begin to roll. I know that the ball ...
- 115
3
votes
2
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151
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How to subtract a list from certain sublists of a list? [closed]
I have a problem in doing an operation on this vector
{{2,3},{3,4},{5,6}}-{1,1}
I want to minus this to get the result
...
- 85
1
vote
1
answer
154
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Solving equation set with vectors
I have six unit vectors in real $3$D space
v1,v2,v3,v4,v5,v6;
Represent the dot product between some of the vectors as the Cos ...
- 422
0
votes
1
answer
63
views
0
votes
1
answer
40
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Reduce expressions into (simplified) matrix and vector forms
I have some computation that results in a rather complicated looking expression that could be much simplified by converting it into matrix or vector expressions. For example, instead of ...
- 206
2
votes
1
answer
134
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Dot Product of Vector with matrix components
In Physics it's common to write matrices in vector components to simplify notation. This commonly occures with the pauli vector $\vec\sigma = \begin{pmatrix}\sigma_1 & \sigma_2 & \sigma_3\end{...
- 1,121
0
votes
1
answer
65
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Finding the Curvature of the path of a particle
How do I find the curvature of the vector when t=5?
The function is:
v[t_] := {2 t^4 + 2, 6 t^3 + 1, 3 t^2 + 4}
- 115
2
votes
0
answers
62
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Finding the Torsion given a vector r[t]
How do I find the torsion of a vector?
The function is:
r[t_]:={Sin[7t],t^4,Cos[7t]}
- 115
1
vote
2
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75
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How would I find the Binormal vector? [duplicate]
How would I find the Binormal vector if r[t_]:={sin(7t),t^4,cos(7t)} in Mathematica?
This is the Mathematica code I have:
...
- 115
1
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0
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40
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I am searching for the Eigen stuff of a non linear transformation
I have a slightly odd problem I have been working on as part of a project on probability models. The full problem itself is not relevant but here is where I am stuck.
I have a 6D space $P$, where all ...
- 111
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0
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43
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How would you write a electric field in cylindrical coordinates?
I am new to Mathematica and I am trying to automate the process of finding electric and magnetic fields for TE and TM modes in a cylindrical superconducting cavity. I could not find documentation ...
4
votes
2
answers
270
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Is it possible to solve vector equations?
For example if we define parametric line segment
curve1[t_, p1_, p2_] := t*p2 + (1 - t)*p1;
where p1 and ...
- 725
2
votes
1
answer
151
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Writing a system of ODEs in vector form
I have the following system:
$\frac{dx}{dt} = p_x \\ \frac{dy}{dt} = p_y \\ \frac{dp_x}{dt}=-\frac{\partial V}{\partial x} \\ \frac{dp_y}{dt}=-\frac{\partial V}{\partial y}$
,where $V(x,y) = \frac{1}{...
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1
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How can I remove the attributes "Orderless" from function Times stably and reliably?
Recently I have been doing some algebra of partitioned matrices, where product like below is common:
where $A_{11}, A_{12}, X, Y$ are all partitioned matrix blocks thus all are matrices in essence.
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0
votes
1
answer
107
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dot product and norm [closed]
Can you solve the following problem in mathematica program? Thank you.
Let x=(x1,x2,x3),y=(y1,y2,y3) and ⟨x,y⟩=x1y1+2x2y2+x3y3 be an inner product in a three-dimensional real vector space.
Define the ...
- 13
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0
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63
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Can I use assumptions to declare a variable's type?
I'm trying to declare $P$ as a vector. I searched for a while, the closest way seems to be Assumptions:
...
- 174
2
votes
0
answers
90
views
Bug with ListVectorPlot in 12.3.1?
Bug fixed in 13.0.0
The documentation shows that result of
...
- 271
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0
answers
47
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Why does the dot product between a matrix and a vector not work? [duplicate]
Executing this code:
...
- 2,911
3
votes
1
answer
120
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How can I do operations in this basis (using matrices)? [closed]
Let's define
$u=t+1/2$
$v=t-1/2$
Now, I have vectors in the basis $e_n=u^n-v^n$, I want to apply functions to such expressions, but as a result get expressions in the same basis again.
For instance, $...
- 2,911
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vote
0
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54
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How to generate a Gaussian random velocity field
Let us assume we have a 2-dimensional velocity field $\textbf{u}=(u_x,u_y)$ defined via its stream function $\psi(\textbf{x})$ as
\begin{cases}
u_x=\partial_y\psi(\textbf{x}) \\
u_y=-\partial_x\psi(\...
- 81
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votes
0
answers
80
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piecewise vector field and composition of piecewise functions
I have the following vector field
...
- 41
0
votes
2
answers
61
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FindRoot with vector function
I have trouble with FindRoot for vector variables, I have search MMA SE find a solution. in Szabolcs‘s code, Vector FindRoot ...
- 445
1
vote
1
answer
55
views
Why doesn't my code evaluate element of a vector at a given t?
I have written a code to solve the Shrodinger equation for a particular three level siystem in two ways: the first way I defined three functions C1[t], C2[t], C3[t] and I solved three ODEs;
the ...
- 31
1
vote
1
answer
49
views
Interpolate function against time
I have two vectors called lammdaWind11 and timeWind11. They are of size 51*1. I have interpolted each one independently as
...
- 115
0
votes
0
answers
61
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velocity four-vector definition by xAct
I want to define the velocity vector by the following relation and evaluate the norm of the vector by using the Minkowski metric.
I have defined the tensor x (position tensor) in xAct, but I don't ...
0
votes
0
answers
64
views
Is it possible to generate a random vector space in Mathematica?
The idea is that I’d like to try to use Mathematica to work through proofs. So if a proof says, “Let there be a vector space V…”, I would like to see a concrete representation of that vector space in ...
- 101
0
votes
1
answer
50
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Plotting two vector fields $\vec V_1=-y\hat i+x \hat j$ and $\vec V_1=2\vec V_1$ on the same plot
I want to compare how two vector fields $\vec V_1=-y\hat i+x \hat j$ and $\vec V_1=2\vec V_1=2(-y\hat i+x \hat j)$ various concentric circles $x^2+y^2=a^2$ with $a^2=1,2,3$ etc. I can plot them ...
- 157
1
vote
3
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73
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Drawing circles on top of a vector field drawn using VectorPlot
I am using the command
VectorPlot[{{y, -x}}, {x, -4, 4}, {y, -4, 4}]
to plot the vector field $\vec{V}=y\hat{i}-x\hat{j}$. On top of this, I need to draw circles of radii $1,2,3...$, etc. I am no ...
- 157
0
votes
2
answers
83
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How to find a matrix satisfying following equation
I have a $N \times 1$ vector $F(t)$ for $0\leq t \leq 1$.
I want to find a $N\times N$ Matrix $C$ (a real-valued matrix) satisfying the following equation:
$$\int_0^t F(t_0)dt_0= C.F(t)$$
If it ...
- 513
3
votes
0
answers
61
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Using ColorFunction Rasterizes the plot
When I make a simple plot using ColorFunction, the Mathematica rasterize the plot. Is anyone else having this issue? Does anyone know a way to avoid this?
...
- 31
1
vote
1
answer
148
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how to rotate a 3D vector around arbitrary axis
I have three vectors red, blue, and green and their origins are at (x,y,z) where red and blue are perpendicular and can be rotated together in the x-y plane by ...
- 3,211
1
vote
1
answer
113
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Generate a normalized Haar-random vector
What is the procedure to generate a random qutrit quantum state?
That is, I want to generate a $3 \times 1$ vector $u$ such that $u$ is generated by a Haar random $3 \times 3$ unitary $U$ multiplied ...
- 175
2
votes
4
answers
110
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multi-dimensional interpolating function evaluation and extract dimension
I have an interpolating function which output dimension is greater than 1, so it's a vector. I get it as the result of a NDSolveValue. The problem is that I'm not able to Evaluate it. I would obtain ...
